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Hello Mr Leballeur,
in the fes-slev.c example, from the fes librairy, that makes tide predictions in a point :I've changed the wgs84 coordinates of that point. I just used a land point : far from the English Channel. However the fes2014 stil make predictions of tide...strange !. Do you have experianced that kind of problem.
regards

Hello Ekechijioke,
Five months ago, I've faced some difficulties to well build the fes librairy. This is why I moved to the TPXO model. But now, I'am back to the feslib.
I've 1 question for you :
I've build the example fes_slev.c and exucted it....it works fine .... then I just made some changes on the point's coordinates : I've made sure that the new point is located in the land (far from the english channel: lat = 49.178 and long = -1.248 ). Surprinsgly, the feslib made the tide prediction on this point ... strange !

The 2nd question is : how to make tide prediction (water level + current magnitude and direction) for many points and how to extract harmonic constants for each. And where feslib sore the predictions

I thank you in advance, and be sure that any help will be appreciated
Mourad

Hello Mourad,

Regarding Q1:
I have not tried inputting points located on land. However, I am not surprised the model is producing readings for these points.
The last time I used FES2014 was to produce tidal data at the mouth of an estuary (coastal region). My results produced reasonable agreement with measured data after I adjusted the readings by 10 days.

Regarding Q2: bitbucket.org/cnes_aviso/fes

After installing the FES lib:

a. to make predictions for many points will entail editing the C script (fes/examples/fes_slev.c). The example file is written to extract readings for a point. You can edit the code or run it severally for different points.

bi. choosing the harmonic constituents to consider can be done by selecting the constituents you will like to consider in fes/test/fes.ini. This file will be called when you run your C script.

bii. I extracted the harmonic constants (amplitude and phase) for each point using the software "Panoply". It reads netCDF files and extracts information from it. www.giss.nasa.gov/tools/panoply/

Aviso recommends other software for reading netCDF:
www.aviso.altimetry.fr/en/data/tools/software.html

c. I ran the script and stored the results in a text file. (e.g. ./fes_slev > result.txt)

Regards,
Chijioke.

Hello Chijioke.
Thank you for your very helpful information.
a - I removed all the harmonics in the 'fes.in' except 'M2_radial.nc', 'M2_tide.nc', 'S2_radial.nc', 'S2_tide.nc' and I compiled/ran the example : it works very fine for tide predictions. The real tide column in the table of predictions is the last one : 'Rad_Tide' ? isn't it ?

b - if the point in the 'fes_slev.c' is not a node of the native grid, dose the librairy make interpolation of the tide preditions i the surrounding nodes?

b -I see an example with python to manage the tidal currents (u,v) : you can find out this script '/fes/python/examples/fes_uv.py' , however I don't have numpy, matplotlib, etc. and their installation on our cluster needs time.... Have you done any current predictions with 'fes_slev.c'
Thank you in advance
Regards
Mourad

Hi Mourad,

a. From the prediction table: Pure_tide is the tide as seen by a tide guage; Geo_Tide is tide as seen by a satellite; and Rad_Tide is the difference between Pure_Tide and Geo_Tide; it represents "Ocean Tide Loading" (goo.gl/WDg7vN). The unit for the tide measurement is centimetres. When converted to metres, the difference is relatively negligible.

Depending on what you're working on Pure_Tide or Geo_Tide would likely be your go to.

b. Yes. It doesn't have to be on a node.

c. I have not used the fes library using python. I see it is possible as described on their webpage but I use C.
I have not done any current prediction.

Regards,
Chijioke.

Hi,

have you got this error when you run the fes_slev.c ? i don't know where is the problem

<pre>fes_slev.c:(.text+0x71) : référence indéfinie vers « fes_new »
fes_slev.c:(.text+0x81) : référence indéfinie vers « fes_error »
fes_slev.c:(.text+0xb7) : référence indéfinie vers « fes_new »
fes_slev.c:(.text+0xc7) : référence indéfinie vers « fes_error »
fes_slev.c:(.text+0x184) : référence indéfinie vers « fes_core »
fes_slev.c:(.text+0x194) : référence indéfinie vers « fes_errno »
fes_slev.c:(.text+0x1a9) : référence indéfinie vers « fes_error »
fes_slev.c:(.text+0x1ff) : référence indéfinie vers « fes_core »
fes_slev.c:(.text+0x20f) : référence indéfinie vers « fes_errno »
fes_slev.c:(.text+0x224) : référence indéfinie vers « fes_error »
fes_slev.c:(.text+0x2fd) : référence indéfinie vers « fes_delete »
fes_slev.c:(.text+0x309) : référence indéfinie vers « fes_delete »

Regards
Imad